The Three Doctors unite to battle an old enemy. Vital cosmic energy is draining into a black hole, and the only hope of the Timelords is Doctor Who. But he is trapped in the Tardis and his only way out is to break the first law of Time.

The Doctor's past incarnations are being snatched out of time and space and transported to the Death Zone on Gallifrey, where they are reunited with some old friends and pitted against their deadliest enemies in the Game of Rassilon. Someone is manipulating the Doctor and his companions in order to claim the most ancient and powerful secret of the Time Lords, but can they survive the challenges and uncover the traitor before it is too late?